docs: def compile(**kwargs):
      r"""There are three modes of parameters :func:`compile()` can take:
      ``string``, ``filename``, and ``dirname``.
  
      The ``string`` parameter is the most basic way to compile Sass.
      It simply takes a string of Sass code, and then returns a compiled
      CSS string.
  
      :param string: Sass source code to compile.  it's exclusive to
                     ``filename`` and ``dirname`` parameters
      :type string: :class:`str`
      :param output_style: an optional coding style of the compiled result.
                           choose one of: ``'nested'`` (default), ``'expanded'``,
                           ``'compact'``, ``'compressed'``
      :type output_style: :class:`str`
      :param source_comments: whether to add comments about source lines.
                              :const:`False` by default
      :type source_comments: :class:`bool`
      :param source_map_contents: embed include contents in map
      :type source_map_contents: :class:`bool`
      :param source_map_embed: embed sourceMappingUrl as data URI
      :type source_map_embed: :class:`bool`
      :param omit_source_map_url: omit source map URL comment from output
      :type omit_source_map_url: :class:`bool`
      :param source_map_root: base path, will be emitted in source map as is
      :type source_map_root: :class:`str`
      :param include_paths: an optional list of paths to find ``@import``\ ed
                            Sass/CSS source files
      :type include_paths: :class:`collections.abc.Sequence`
      :param precision: optional precision for numbers. :const:`5` by default.
      :type precision: :class:`int`
      :param custom_functions: optional mapping of custom functions.
                               see also below `custom functions
                               <custom-functions_>`_ description
      :type custom_functions: :class:`set`,
                              :class:`collections.abc.Sequence`,
                              :class:`collections.abc.Mapping`
      :param custom_import_extensions: (ignored, for backward compatibility)
      :param indented: optional declaration that the string is Sass, not SCSS
                       formatted. :const:`False` by default
      :type indented: :class:`bool`
      :returns: the compiled CSS string
      :param importers: optional callback functions.
                       see also below `importer callbacks
                       <importer-callbacks_>`_ description
      :type importers: :class:`collections.abc.Callable`
      :rtype: :class:`str`
      :raises sass.CompileError: when it fails for any reason
                                 (for example the given Sass has broken syntax)
  
      The ``filename`` is the most commonly used way.  It takes a string of
      Sass filename, and then returns a compiled CSS string.
  
      :param filename: the filename of Sass source code to compile.
                       it's exclusive to ``string`` and ``dirname`` parameters
      :type filename: :class:`str`
      :param output_style: an optional coding style of the compiled result.
                           choose one of: ``'nested'`` (default), ``'expanded'``,
                           ``'compact'``, ``'compressed'``
      :type output_style: :class:`str`
      :param source_comments: whether to add comments about source lines.
                              :const:`False` by default
      :type source_comments: :class:`bool`
      :param source_map_filename: use source maps and indicate the source map
                                  output filename.  :const:`None` means not
                                  using source maps.  :const:`None` by default.
      :type source_map_filename: :class:`str`
      :param source_map_contents: embed include contents in map
      :type source_map_contents: :class:`bool`
      :param source_map_embed: embed sourceMappingUrl as data URI
      :type source_map_embed: :class:`bool`
      :param omit_source_map_url: omit source map URL comment from output
      :type omit_source_map_url: :class:`bool`
      :param source_map_root: base path, will be emitted in source map as is
      :type source_map_root: :class:`str`
      :param include_paths: an optional list of paths to find ``@import``\ ed
                            Sass/CSS source files
      :type include_paths: :class:`collections.abc.Sequence`
      :param precision: optional precision for numbers. :const:`5` by default.
      :type precision: :class:`int`
      :param custom_functions: optional mapping of custom functions.
                               see also below `custom functions
                               <custom-functions_>`_ description
      :type custom_functions: :class:`set`,
                              :class:`collections.abc.Sequence`,
                              :class:`collections.abc.Mapping`
      :param custom_import_extensions: (ignored, for backward compatibility)
      :param importers: optional callback functions.
                       see also below `importer callbacks
                       <importer-callbacks_>`_ description
      :type importers: :class:`collections.abc.Callable`
      :returns: the compiled CSS string, or a pair of the compiled CSS string
                and the source map string if ``source_map_filename`` is set
      :rtype: :class:`str`, :class:`tuple`
      :raises sass.CompileError: when it fails for any reason
                                 (for example the given Sass has broken syntax)
      :raises exceptions.IOError: when the ``filename`` doesn't exist or
                                  cannot be read
  
      The ``dirname`` is useful for automation.  It takes a pair of paths.
      The first of the ``dirname`` pair refers the source directory, contains
      several Sass source files to compiled.  Sass source files can be nested
      in directories.  The second of the pair refers the output directory
      that compiled CSS files would be saved.  Directory tree structure of
      the source directory will be maintained in the output directory as well.
      If ``dirname`` parameter is used the function returns :const:`None`.
  
      :param dirname: a pair of ``(source_dir, output_dir)``.
                      it's exclusive to ``string`` and ``filename``
                      parameters
      :type dirname: :class:`tuple`
      :param output_style: an optional coding style of the compiled result.
                           choose one of: ``'nested'`` (default), ``'expanded'``,
                           ``'compact'``, ``'compressed'``
      :type output_style: :class:`str`
      :param source_comments: whether to add comments about source lines.
                              :const:`False` by default
      :type source_comments: :class:`bool`
      :param source_map_contents: embed include contents in map
      :type source_map_contents: :class:`bool`
      :param source_map_embed: embed sourceMappingUrl as data URI
      :type source_map_embed: :class:`bool`
      :param omit_source_map_url: omit source map URL comment from output
      :type omit_source_map_url: :class:`bool`
      :param source_map_root: base path, will be emitted in source map as is
      :type source_map_root: :class:`str`
      :param include_paths: an optional list of paths to find ``@import``\ ed
                            Sass/CSS source files
      :type include_paths: :class:`collections.abc.Sequence`
      :param precision: optional precision for numbers. :const:`5` by default.
      :type precision: :class:`int`
      :param custom_functions: optional mapping of custom functions.
                               see also below `custom functions
                               <custom-functions_>`_ description
      :type custom_functions: :class:`set`,
                              :class:`collections.abc.Sequence`,
                              :class:`collections.abc.Mapping`
      :param custom_import_extensions: (ignored, for backward compatibility)
      :raises sass.CompileError: when it fails for any reason
                                 (for example the given Sass has broken syntax)
  
      .. _custom-functions:
  
      The ``custom_functions`` parameter can take three types of forms:
  
      :class:`~set`/:class:`~collections.abc.Sequence` of \
      :class:`SassFunction`\ s
         It is the most general form.  Although pretty verbose, it can take
         any kind of callables like type objects, unnamed functions,
         and user-defined callables.
  
         .. code-block:: python
  
            sass.compile(
                ...,
                custom_functions={
                    sass.SassFunction('func-name', ('$a', '$b'), some_callable),
                    ...
                }
            )
  
      :class:`~collections.abc.Mapping` of names to functions
         Less general, but easier-to-use form.  Although it's not it can take
         any kind of callables, it can take any kind of *functions* defined
         using :keyword:`def`/:keyword:`lambda` syntax.
         It cannot take callables other than them since inspecting arguments
         is not always available for every kind of callables.
  
         .. code-block:: python
  
            sass.compile(
                ...,
                custom_functions={
                    'func-name': lambda a, b: ...,
                    ...
                }
            )
  
      :class:`~set`/:class:`~collections.abc.Sequence` of \
      named functions
         Not general, but the easiest-to-use form for *named* functions.
         It can take only named functions, defined using :keyword:`def`.
         It cannot take lambdas sinc names are unavailable for them.
  
         .. code-block:: python
  
            def func_name(a, b):
                return ...
  
            sass.compile(
                ...,
                custom_functions={func_name}
            )
  
      .. _importer-callbacks:
  
      Newer versions of ``libsass`` allow developers to define callbacks to be
      called and given a chance to process ``@import`` directives. You can
      define yours by passing in a list of callables via the ``importers``
      parameter. The callables must be passed as 2-tuples in the form:
  
      .. code-block:: python
  
          (priority_int, callback_fn)
  
      A priority of zero is acceptable; priority determines the order callbacks
      are attempted.
  
      These callbacks can accept one or two string arguments. The first argument
      is the path that was passed to the ``@import`` directive; the second
      (optional) argument is the previous resolved path, where the ``@import``
      directive was found. The callbacks must either return ``None`` to
      indicate the path wasn't handled by that callback (to continue with others
      or fall back on internal ``libsass`` filesystem behaviour) or a list of
      one or more tuples, each in one of three forms:
  
      * A 1-tuple representing an alternate path to handle internally; or,
      * A 2-tuple representing an alternate path and the content that path
        represents; or,
      * A 3-tuple representing the same as the 2-tuple with the addition of a
        "sourcemap".
  
      All tuple return values must be strings. As a not overly realistic
      example:
  
      .. code-block:: python
  
          def my_importer(path, prev):
              return [(path, '#' + path + ' { color: red; }')]
  
          sass.compile(
                  ...,
                  importers=[(0, my_importer)]
              )
  
      Now, within the style source, attempting to ``@import 'button';`` will
      instead attach ``color: red`` as a property of an element with the
      imported name.
  
      .. versionadded:: 0.4.0
         Added ``source_comments`` and ``source_map_filename`` parameters.
  
      .. versionchanged:: 0.6.0
         The ``source_comments`` parameter becomes to take only :class:`bool`
         instead of :class:`str`.
  
      .. deprecated:: 0.6.0
         Values like ``'none'``, ``'line_numbers'``, and ``'map'`` for
         the ``source_comments`` parameter are deprecated.
  
      .. versionadded:: 0.7.0
         Added ``precision`` parameter.
  
      .. versionadded:: 0.7.0
         Added ``custom_functions`` parameter.
  
      .. versionadded:: 0.11.0
         ``source_map_filename`` no longer implies ``source_comments``.
  
      .. versionadded:: 0.17.0
         Added ``source_map_contents``, ``source_map_embed``,
         ``omit_source_map_url``, and ``source_map_root`` parameters.
  
      .. versionadded:: 0.18.0
          The importer callbacks can now take a second argument, the previously-
          resolved path, so that importers can do relative path resolution.
  
      """
      modes = set()
      for mode_name in MODES:
          if mode_name in kwargs:
              modes.add(mode_name)
      if not modes:
          raise TypeError('choose one at least in ' + and_join(MODES))
      elif len(modes) > 1:
          raise TypeError(
              and_join(modes) + ' are exclusive each other; '
              'cannot be used at a time',
          )
      precision = kwargs.pop('precision', 5)
      output_style = kwargs.pop('output_style', 'nested')
      if not isinstance(output_style, string_types):
          raise TypeError(
              'output_style must be a string, not ' +
              repr(output_style),
          )
      try:
          output_style = OUTPUT_STYLES[output_style]
      except KeyError:
          raise CompileError(
              '{} is unsupported output_style; choose one of {}'
              ''.format(output_style, and_join(OUTPUT_STYLES)),
          )
      source_comments = kwargs.pop('source_comments', False)
      if source_comments in SOURCE_COMMENTS:
          if source_comments == 'none':
              deprecation_message = (
                  'you can simply pass False to '
                  "source_comments instead of 'none'"
              )
              source_comments = False
          elif source_comments in ('line_numbers', 'default'):
              deprecation_message = (
                  'you can simply pass True to '
                  "source_comments instead of " +
                  repr(source_comments)
              )
              source_comments = True
          else:
              deprecation_message = (
                  "you don't have to pass 'map' to "
                  'source_comments but just need to '
                  'specify source_map_filename'
              )
              source_comments = False
          warnings.warn(
              "values like 'none', 'line_numbers', and 'map' for "
              'the source_comments parameter are deprecated; ' +
              deprecation_message,
              FutureWarning,
          )
      if not isinstance(source_comments, bool):
          raise TypeError(
              'source_comments must be bool, not ' +
              repr(source_comments),
          )
      fs_encoding = sys.getfilesystemencoding() or sys.getdefaultencoding()
  
      def _get_file_arg(key):
          ret = kwargs.pop(key, None)
          if ret is not None and not isinstance(ret, string_types):
              raise TypeError('{} must be a string, not {!r}'.format(key, ret))
          elif isinstance(ret, text_type):
              ret = ret.encode(fs_encoding)
          if ret and 'filename' not in modes:
              raise CompileError(
                  '{} is only available with filename= keyword argument since '
                  'has to be aware of it'.format(key),
              )
          return ret
  
      source_map_filename = _get_file_arg('source_map_filename')
      output_filename_hint = _get_file_arg('output_filename_hint')
  
      source_map_contents = kwargs.pop('source_map_contents', False)
      source_map_embed = kwargs.pop('source_map_embed', False)
      omit_source_map_url = kwargs.pop('omit_source_map_url', False)
      source_map_root = kwargs.pop('source_map_root', None)
  
      if isinstance(source_map_root, text_type):
          source_map_root = source_map_root.encode('utf-8')
  
      # #208: cwd is always included in include paths
      include_paths = (os.getcwd(),)
      include_paths += tuple(kwargs.pop('include_paths', ()) or ())
      include_paths = os.pathsep.join(include_paths)
      if isinstance(include_paths, text_type):
          include_paths = include_paths.encode(fs_encoding)
  
      custom_functions = kwargs.pop('custom_functions', ())
      if isinstance(custom_functions, collections_abc.Mapping):
          custom_functions = [
              SassFunction.from_lambda(name, lambda_)
              for name, lambda_ in custom_functions.items()
          ]
      elif isinstance(
              custom_functions,
              (collections_abc.Set, collections_abc.Sequence),
      ):
          custom_functions = [
              func if isinstance(func, SassFunction)
              else SassFunction.from_named_function(func)
              for func in custom_functions
          ]
      else:
          raise TypeError(
              'custom_functions must be one of:\n'
              '- a set/sequence of {0.__module__}.{0.__name__} objects,\n'
              '- a mapping of function name strings to lambda functions,\n'
              '- a set/sequence of named functions,\n'
              'not {1!r}'.format(SassFunction, custom_functions),
          )
  
      if kwargs.pop('custom_import_extensions', None) is not None:
          warnings.warn(
              '`custom_import_extensions` has no effect and will be removed in '
              'a future version.',
              FutureWarning,
          )
  
      importers = _validate_importers(kwargs.pop('importers', None))
  
      if 'string' in modes:
          string = kwargs.pop('string')
          if isinstance(string, text_type):
              string = string.encode('utf-8')
          indented = kwargs.pop('indented', False)
          if not isinstance(indented, bool):
              raise TypeError(
                  'indented must be bool, not ' +
                  repr(source_comments),
              )
          _check_no_remaining_kwargs(compile, kwargs)
          s, v = _sass.compile_string(
              string, output_style, source_comments, include_paths, precision,
              custom_functions, indented, importers,
              source_map_contents, source_map_embed, omit_source_map_url,
              source_map_root,
          )
          if s:
              return v.decode('utf-8')
      elif 'filename' in modes:
          filename = kwargs.pop('filename')
          if not isinstance(filename, string_types):
              raise TypeError('filename must be a string, not ' + repr(filename))
          elif not os.path.isfile(filename):
              raise IOError('{!r} seems not a file'.format(filename))
          elif isinstance(filename, text_type):
              filename = filename.encode(fs_encoding)
          _check_no_remaining_kwargs(compile, kwargs)
          s, v, source_map = _sass.compile_filename(
              filename, output_style, source_comments, include_paths, precision,
              source_map_filename, custom_functions, importers,
              output_filename_hint,
              source_map_contents, source_map_embed, omit_source_map_url,
              source_map_root,
          )
          if s:
              v = v.decode('utf-8')
              if source_map_filename:
                  source_map = source_map.decode('utf-8')
                  v = v, source_map
              return v
      elif 'dirname' in modes:
          try:
              search_path, output_path = kwargs.pop('dirname')
          except ValueError:
              raise ValueError(
                  'dirname must be a pair of (source_dir, '
                  'output_dir)',
              )
          _check_no_remaining_kwargs(compile, kwargs)
          s, v = compile_dirname(
              search_path, output_path, output_style, source_comments,
              include_paths, precision, custom_functions, importers,
              source_map_contents, source_map_embed, omit_source_map_url,
              source_map_root,
          )
          if s:
              return
      else:
          raise TypeError('something went wrong')
      assert not s
      raise CompileError(v)